Polycythaemia rubra vera in monozygotic twins.
D000368:Aged; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011087:Polycythemia Vera / Q000235:genetics*; D011247:Pregnancy; D014430:Twins, Monozygotic